(1) In recent years, technologies of storing heat energy, that is, heat-storage technologies attract attention as those solving present-day energy problems. The heat-storage technologies are technologies of effectively utilizing natural energy such as solar heat, geothermal heat etc. and remaining heat from cooling/heating equipments, and are utilized for example as technologies in which inexpensive nighttime power is utilized in a house to store heat and utilized as a multi-purpose heat source to reduce consumption in daytime electric power.
Heat-storage materials used in such heat-storage technologies include sensible heat-storage materials and latent heat-storage materials, and particularly the latent heat-storage materials utilizing latent heat resulting from the phase change of a substance are often used.
These latent heat-storage materials store heat (heat storage) upon phase change of a substance from solid to liquid and release heat (heat release) upon phase change from liquid to solid, and by utilizing this property, heat is stored and released. Generally, many latent heat-storage materials undergo phase change (solid/liquid change) in the temperature range of 15 to 50° C. Accordingly, the latent heat-storage material should be handled as liquid and used generally by encapsulating it in a liquid state in a laminate sheet or plastic case capable of being closed.
Although the size of such laminate sheet and plastic case is limited to a predetermined dimension, processing such as cutting is not feasible due to leakage of the latent heat-storage material. Application by nailing is not feasible due to leakage of the latent heat-storage material. When the laminate sheet or plastic case is fixed perpendicularly, the heat-storage material is distributed in higher density at the bottom, so there is a problem that the heat-storage material cannot be effectively utilized.
Therefore, the heat-storage material is exclusively horizontally disposed for use as typified by the heat-storage material used for floor heating in a heat-storage system under the present circumstances.
Against such problem, Patent Literature 1 proposes a heat-storage object comprising latent heat-storage capsules supported on a coating film or a sheet, thereby enabling processing such as cutting or application by nailing and preventing the heat-storage material from being distributed in higher density at the bottom, while in Non-Patent Literature 1, the above problem is solved by mixing a encapsulated latent heat-storage material with a material such as plasterboard and then fixing it via an inorganic binder or resin. In Patent Literature 2, on the other hand, a heat-storage material is supported on a porous material in order to solve the above problem and achieve sufficient heat-storage property.
(2) Glass, resin boards, metal plates etc. are used in various fields and become essential in our living spaces, for example in plate glasses, floors, walls and ceilings in housings, offices and greenhouses. In housings and offices, for example, plate glasses, walls and the like separate the room from the outside world, and in summer and during daylight, warm air of the outside world is shut out and the living space is made comfortable by a cooler etc. In winter and at night, cold air of the outside world is shut out and the living space is made comfortable by a heater etc. In a greenhouse etc., glass or the like separates the house from the outside world, and the temperature in the house can be controlled as desired.
However, when a material of high heat conductivity, such as glass, is used in housings, offices, greenhouses etc., cool air in the room is easily warmed by warm air of the outside world in summer or during daylight. In winter and at night, on the other hand, warm air in the room is easily cooled by cold air of the outside world, and consequently, excessive heating or cooling energy should be used.
In Patent Literature 3, insulation in the room is improved by laminating a heat insulating sheet on glass in order to solve the problem. In Patent Literature 4, insulating property in the room is improved by arranging an air layer, a vacuum layer and a low-emissivity layer between glasses.
(3) As technologies of controlling heat energy, there are heat insulation technologies in addition to the heat-storage technologies, and as materials utilizing such heat-storage technologies and heat insulation technologies, for example in the field of housing, there are known materials used in energy-saving housings wherein inexpensive nighttime power is utilized to store heat and utilized as a general-purpose heat source, thereby reducing daytime power consumption, while the influence of outside air temperature is shut out to reduce a fluctuation in room temperature.
For example, Patent Literature 5 describes a building frame panel provided with a heat insulator in the exterior side and with a latent heat-storage material in the interior side, thereby attempting at energy saving for heating and cooling energy in a housing. In Patent Literature 5, a latent heat-storage material hermetically sealed in a casing is laminated with a heat insulator. Patent Literature 6 describes a frame structure wherein a heat insulator in the exterior side is used in combination with a heat-storage object consisting of a latent heat-storage material in the interior side, which reduces a fluctuation in room temperature against outside air temperature and maintains a comfortable indoor condition, thereby attempting at saving energy required for cooling and heating. In Patent Literature 6, a microencapsulated latent heat-storage material is used as the heat-storage object.
(4) With rising concern of housing environment in recent years, there are rapidly increasing housings provided with a floor heating system where a heat source such as a heating wire and a hot-water pipe is provided in a floor. In the floor heating system, heat generated by a heat source such as a heating wire and a hot-water pipe is used to warm the interior space, and particularly when a heating wire is used, considerable power consumption is necessary for heating the floor.
As one solution of such problem, there is a heat-storage-type floor heating system having a heat-storage material introduced into a floor heating system. A majority of latent heat-storage materials used in the heat-storage-type floor heating system are those for storing heat (heat storage) upon phase change thereof from solid to liquid and for releasing heat (heat release) upon phase change from liquid to solid, and many of them undergo phase change (solid/liquid change) generally in the temperature range of 15 to 50° C.
When such latent heat-storage materials are used in a floor heating system, for example, it is possible to use inexpensive nighttime power, to storage heat, and release the heat gradually in the daytime thereby reducing power consumption. Once the latent heat-storage materials are warmed, they can keep the temperature constant for a long time, thus enabling reduction in power consumption and maintenance of a comfortable living environment.
As the floor heating system utilizing latent heat-storage materials, for example, Patent Literature 7 describes use of cased latent heat-storage materials.
(5) Patent Literature 8 discloses a heat-storage object capable of high-frequency heating, which comprises a crystal water-containing hydrate contained in a molten mixture of an ethylene/olefin copolymer and a crystalline organic compound (paraffin).
Patent Literature 1: JP-A 10-311693 (claims)
Non-Patent Literature 1: Design-Series Collected Papers, Architectural Institute of Japan, No. 540, 23-29, February, 2001
Patent Literature 2: JP-A 9-143461
Patent Literature 3: JP-A 11-348169
Patent Literature 4: JP-A 2000-87656
Patent Literature 5: JP-A 61-122354
Patent Literature 6: JP-A 2003-34993
Patent Literature 7: JP-A 2001-304596
Patent Literature 8: Japanese Patent No. 2548850